Starter If x = 3, find y when: a) y = x b) y = 2x c) y = 5x - 2 d) y = x
2 answers:
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Answer:
We have the equation:
3x - 5y = 15
a) We want to create a table with at least 4 points.
To do this, first, let's write the equation as a function: We must isolate one of the variables. Let's isolate y.
5y = 3x - 15
y = (3/5)*x - 3.
Then we have a linear equation.
Now, we can input different values of x, and see what value takes y in each case, then in this way we can be sure that the points will be on the line.
x = 0.
y = (3/5)*0 - 3
y = -3
Then we have the point (0, -3).
x = 1.
y = (3/5)*1 - 3 = 3/5 - 15/5 = -12/5
y = -12/5
Then we have the point (1, -12/5)
x = 5
y = (3/5)*5 - 3 = 3 - 3 = 0
y = 0
then we have the point (5, 0)
x = 10
y = (3/5)*10 - 3 = 6 - 3 = 3
y = 3
Then we have the point (10, 3).
Now we can create the table
Below you can see a graph, where the blue dots are our 4 points, and the green line is the line that represents the equation.
